Many industrial and commercial plants and government and private research and industrial facilities perform potentially dangerous processes. Automated warning and alarm systems alert personnel to dangerous or abnormal conditions inside or near a plant so that the personnel may take prompt protective action such as evacuation, co-location or shelter in place. Such automated systems include simple fire and smoke detectors that detect the presence of fire or smoke and immediately activate a connected, audible alarm confined to a specific area of a plant. Many systems include a central hub for receiving detection signals from a plurality of detectors for detecting a plurality of different hazards located throughout a plant. In some systems the central hub also is connected to a network of alarms including audible alarms, both siren-like and information-based, and visual alarms, including flashing emergency lights and textual-based information screens.
Unfortunately, in some environments, currently-available automated warning and alert systems are not entirely effective. For example, they may not provide complete notification coverage over a wide area, or they may not provide for personal accountability during an emergency alert. What are needed therefore are improved systems for alerting persons of impending or actual hazardous conditions that could endanger their safety.